I believe you misunderstood how it works. A parent certificate cannot be used to decrypt information encrypted by a child certificate… the CA issuer just signs your child certificate, it doesn’t have access to your private key.
Then, everyone who trusts the CA will trust your certificate by checking it is signed by the CA who should have done the checks to ensure your certificate contains truthful data.
So your layman description of “they have secret codes to everyone’s encryption” is completely wrong.
Then, everyone who trusts the CA will trust your certificate by checking it is signed by the CA who should have done the checks to ensure your certificate contains truthful data.
So your layman description of “they have secret codes to everyone’s encryption” is completely wrong.